MW3 host hack

I was searching a game today (S&D) when i joined a lobby.
After i died i discoverd that, my teammate has 2013 bullets and unlimited health 4 trophy systems and 4 claymores.
I thought this is a bug but it seems like the lobby was hacked because in the next round everyone was flying....
So i thought i will ask you guys what kind of hack was that?

I was searching a game today (S&D) when i joined a lobby.
After i died i discoverd that, my teammate has 2013 bullets and unlimited health 4 trophy systems and 4 claymores.
I thought this is a bug but it seems like the lobby was hacked because in the next round everyone was flying....
So i thought i will ask you guys what kind of hack was that?